U.S. Pat. No. 7,527,241 discloses a diaphragm valve having an inlet sleeve and an outlet sleeve that converge to a fluid flow chamber contains a valve seat engaged by an elastic diaphragm that is composed of a peripheral flange connected to a central dome-shaped part. The cross section of the two sleeves near the valve seat is flattened in the direction of flow and elongated in the direction transverse thereto, so to form a substantially elliptical port, corresponding to the dome of the diaphragm, which has the shape of a sector of an ellipsoid. Acknowledgement of the above reference herein is not to be inferred as meaning that these are in any way relevant to the patentability of the presently disclosed subject matter.